The incidence rate of and clinical significance of crevice corrosion is to be determined. A series of orthopaedic implants of the plate and screw internal fixation device type will be followed from the time of insertion to the time of removal. Photographic records of the implant and tissue cultures at both operations will be made. After removal, the devices will be studied metallurgically. Macroscopic, microscopic and mechanical properties evaluations will be performed. The data will be analyzed in an effort to determine: 1. What metallurgical variables, if any, control the degree of crevice corrosion observed 2. Does the crevice corrosion produce adverse clinical effects 3. What is the incidence rate and degree of severity of the crevice corrosion and is there any difference in performance between stainless steel and Chromium-Cobalt alloys in this regard. In addition, a comparison of implants that have been removed for cause with implants that are removed routinely will be made. This will allow a determination if any specific metallurgical characteristics can be related to performance of these type implants.